• 멤브레인
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• 제28권3호
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• pp.205-213
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• 2018

본 연구에서는 가교막을 poly(2,6-dimethyl-1,4-phenylene oxide)(PPO)에 브롬화반응을 통해 제조한 Br-PPO를 주사슬로 성공적으로 제조하였고, 키토산과 4차암모늄이 포함된 키토산을 가교제로 사용하였다. 제조된 가교막은 트리메틸아민 용액에 함침하여 후처리를 진행하였다. 그리고 가교도는 가교제 비율을 이용하여 조절하였다. 이렇게 제조된 A-PPO + chitosan 가교막과 A-PPO + QA-chitosan 가교막의 이온교환막으로써의 가능성을 여러 특성평가로 확인하였다. Chitosan을 사용한 가교막보다 QA-chitosan을 사용한 가교막이 가교가 더 잘 이루어졌으며, QA-chitosan의 함량이 증가할수록 이온교환용량이 1.18 meq/g에서 1.53 meq/g까지 증가하는 경향, 함수율이 21.6%에서 42.2%까지 증가하는 경향을 나타내었다.

• Journal of Korean Dental Science
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• 제15권1호
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• pp.51-60
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• 2022

Purpose: The aim of this study was to evaluate the bio-durability and bone regeneration capacity of the non-cross-linked collagen membrane in rabbit calvarial defect models. Materials and Methods: Four circular defects with 8 mm diameter were made in each of calvarium of 10 male rabbits. The following groups was randomly assigned to each defect - 1) Control, 2) membrane group containing non-cross-linked collagen membrane only (M), 3) bone graft group (B), 4) bone graft with membrane group (B+M). Animals were sacrificed and samples were harvested at 2 weeks (n=5) and 8 weeks (n=5). Histologic sections were prepared and histomorphometric analysis was performed. Result: Histologic results showed well adaptation of the non-cross-linked membrane on each defect and normal healing response at 2 weeks. At 8 weeks, the membranes were partially biodegraded. Histomorphometrically, B and B+M group showed the significantly greater total augmented area (B+M group, 10.44±1.49, P=0.016; B group, 9.13±0.53, P=0.032) and new bone formation (B+M group, 2.89±0.93, P=0.008; B group, 2.85±1.15, P=0.008) compared to control group. Collapsing of the central portion of the membrane, membrane group showed greater value in new bone formation at 8 weeks (1.78±0.68, P=0.032). Conclusion: Within the limitations of this study, the non-cross-linked collagen membrane fabricated using the improved decellularized method was shown to be effective for the regeneration of calvarial bone defects. In addition, prolonged barrier function might be provided using this collagen membrane.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.85.2-85.2
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• 2010

There is widespread effort to develop polymer membranes in place of Nafion for high temperature polymer electrolyte membrane fuel cell(PEMFC). In our study, SiO2 membranes are arranged by electrospinning method. For impregnation solution, the modified sulfonated poly(ether ether ketone)(SPEEK) polymer is prepared from sulfonation, sulfochlorination, partial reduction and lithiation reaction. The modified polymer is cross-linked with 1,4-diiodobetane in NMP solvent and then blended with Heteropoly acid(HPA). The characterization of membranes is confimed by FT-IR, Thermogravimetry(TGA), water uptake test and single cell performance test for PEMFC, etc. The composite membrane shows satisfactory thermal and mechanical properties. Beside, The membrane exhibits good ion exchange capacity and high proton conductivity. As a result, The composite membrane is promising as an alternative membrane in high temperature PEMFC.

• Korean Membrane Journal
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• 제10권1호
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• pp.1-7
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• 2008

Polystyrene-co-divinylbenzene (PS-co-DVB) asymmetric membranes were prepared. In order to control their structure and mechanical properties the degree of cross-linking and the composition of casting solution were varied. The rubber added PS-DVB membranes was also prepared to overcome the mechanical limitation of cross-linked membrane, and their mechanical properties were investigated. It was revealed that the concentration of polymer in the casting solution affected the determination of skin formation. When the PS-co-DVB membrane consists of styrene-butadiene (SB) rubber or liquid polybutadiene (PBD), the structures formed showed that the PS content in the PS/DVB system played an important role in determining the porous sublayer structure.

• Journal of Periodontal and Implant Science
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• 제45권6호
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• pp.229-237
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• 2015

Purpose: The aim of this study was to determine the clinical feasibility of using dehydrothermally cross-linked collagen membrane (DCM) for bone regeneration around peri-implant dehiscence defects, and compare it with non-cross-linked native collagen membrane (NCM). Methods: Dehiscence defects were investigated in twenty-eight patients. Defect width and height were measured by periodontal probe immediately following implant placement (baseline) and 16 weeks afterward. Membrane manipulation and maintenance were clinically assessed by means of the visual analogue scale score at baseline. Changes in horizontal thickness at 1 mm, 2 mm, and 3 mm below the top of the implant platform and the average bone density were assessed by cone-beam computed tomography at 16 weeks. Degradation of membrane was histologically observed in the soft tissue around the implant prior to re-entry surgery. Results: Five defect sites (two sites in the NCM group and three sites in the DCM group) showed soft-tissue dehiscence defects and membrane exposure during the early healing period, but there were no symptoms or signs of severe complications during the experimental postoperative period. Significant clinical and radiological improvements were found in all parameters with both types of collagen membrane. Partially resorbed membrane leaflets were only observed histologically in the DCM group. Conclusions: These findings suggest that, compared with NCM, DCM has a similar clinical expediency and possesses more stable maintenance properties. Therefore, it could be used effectively in guided bone regeneration around dehiscence-type defects.

• 멤브레인
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• 제30권6호
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• pp.395-408
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• 2020

고분자 전해질 막 연료전지(polymer electrolyte membrane fuel cell, PEMFC)는 환경오염물질 배출이 없는 친환경 에너지 변환 장치로 주목을 받고 있다. PEMFC의 구성요소 중 고분자 전해질 막(polymer electrolyte membrane, PEM)은 음극에서 발생되는 수소이온을 양극으로 전달하는 역할과 동시에 분리막으로써 연료의 투과를 차단하는 역할을 수행하는 핵심 소재이다. 대표적으로 Nafion®과 같은 과불소화계 고분자 전해질 막이 상용화 되어있지만 높은 단가 및 분해 시 환경오염물질이 배출되는 단점이 존재하여, 이를 대체할 탄화수소계 고분자를 활용한 전해질 막 개발에 관한 연구들이 수행되고 있다. 높은 수소이온 전도도를 가지며 동시에 우수한 물리·화학적 안정성을 갖는 탄화수소계 고분자 기반 전해질 막을 개발하기 위해 가교 구조가 도입된 전해질 막을 개발하는 연구들이 보고되고 있다. 본 총설은 가교 전해질 막을 제조하기 위해 이온교환 작용기가 도입된 탄화수소계 고분자를 활용하여 다양한 종류의 가교 전해질 막을 제조하는 방법에 대해 논하였다.

• 한국재료학회지
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• 제21권2호
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• pp.125-132
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• 2011

Fibrous chitosan membranes were fabricated as a substrate for skin applications using an electro-spinning process with different solvents and varying concentrations. Scanning electron microscopy (SEM) images confirmed that the formation of the chitosan fibrous membrane in trifluoroacetic acid was better than that in acetic acid. Fourier transform infrared spectroscopy showed that the chitosan fibers were cross-linked with glutaraldehyde, and that the cytotoxicity of the aldehyde groups was reduced by glycine and washing by NaOH and DI water. Chitosan cross-linked fibrous membranes were insoluble in water and could be washed thoroughly to wash away glycine and excess NaOH and prevent the infiltration of other water soluble bio-toxic agents using DI water. MTT assay method was employed to test the cytotoxicity of chitosan membranes during fabricating, treating and washing processes. After the dehydration of cell cultured chitosan membranes, cell attachment behavior on the material was evaluated using SEM method. Effect of the treatment processes on the biocompatibility of the chitosan membranes was shown by comparing of filopodium and lamellipodium of fibroblast cells on grown washed and unwashed chitosan fibrous membrane. The MTT assay and SEM morphology confirmed that the washed chitosan fibrous membrane increased cell attachment and cell growth, and decreased toxicity compared to results for the unwashed chitosan fibrous membrane.

• 멤브레인
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• 제21권3호
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• pp.270-276
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• 2011

기질 고분자인 sulfonated PEEK (sPEEK)와 가교제(cross-linking reagent) 4,4'-ethyldianiline (EdAn), 그래프트제(grafting reagent) 2-phenylethylamine (PEA)을 용매 dimethylacetamide (DMAc)에 녹여 용매증발법을 이용하여 제막하였다. 이민화 반응(imination)과 술폰화(sulfonation) 과정을 거쳐 최종 이온교환막인 cross-linked and grafted sPEEK (CG-sPEEK)막을 제조하였다. FT-IR 분석을 통해 술폰화 및 이민화 반응여부를 확인할 수 있었다. Proton conductivity와 water uptake, volume change를 측정하여 상용화된 Nafion115와 비교함으로써 이온교환막으로서의 활용가능성을 평가하였다. 제조된 CG-sPEEK막의 proton conductivity (0.17 S/cm) 값이 Nafion115 (0.10 S/cm) 보다 우수하게 나타나 이온교환막으로서의 적용가능성을 보여주었다. 다만 높은 water uptake (130%)는 CG-sPEEK의 치수안정성을 위해서 저감시킬 필요가 있다.

• 대한치과의사협회지
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• 제56권12호
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• pp.667-685
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• 2018

Objectives: Aim of this study was to evaluate bone regenerative efficacy of a chemically cross-linked porcine collagen membrane (CM) when used in combination with highly soluble biphasic calcium phosphate (BCP). Materials and methods: Physiochemical properties of the experimental collagen membrane were analyzed. Four circumferential defects with diameter of 8 mm were created in each calvarium of New Zealand white rabbits (n = 10). Defects were randomly allocated to one of following 4 groups: 1) BCP-CM (BCP (20% hydroxyapatite/80% ${\beta}$-tricalcium phosphate) covered with the prepared collagen membrane), 2) BCP (only BCP used), 3) CM (only the prepared collagen membrane used), and 4) C (control; only blood clot). After 2 weeks (n = 5) and 8 weeks (n = 5), histologic and histomorphometric analyses were performed. Results: The experimental collagen membrane exhibited dense and compact structure, relatively high tensile strength and lower degradability. Histologic analyses revealed that new bone increased rapidly at 2 weeks, while defect was preserved at 8 weeks. Histomorphometric analyses revealed that the new bone areas increased in the BCP-grafted groups over 8 weeks, with BCP-CM exhibiting greater total augmented area than that of BCP group both at 2 weeks ($27.12{\pm}3.99$ versus $21.97{\pm}2.27mm^2$) and 8 weeks ($25.75{\pm}1.82$ versus $22.48{\pm}1.10mm^2$) (P < 0.05). Conclusions: The experimental collagen membrane successfully preserved localized defect for 8 weeks despite early rapid resorption of BCP. Within the study limitations, combined use of the chemically cross-linked porcine collagen membrane and highly soluble BCP aided localized bone regeneration.

• 한국수소및신에너지학회논문집
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• 제28권4호
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• pp.338-344
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• 2017

Polyoxometal molybdophosphoric acid (MoPA) bonded polyether ether ketone (PEEK) composite membrane for water electrolysis has been investigated. The composited membrane, covalently cross linked (CL) sulfonated polyether ether ketone (SPEEK) with a bonded MoPA, was prepared in sulfonation of PEEK, cross linkage reaction with 1,4-diiodobutane, and addition with MoPA. PEEK was covalently cross-linked with 1,4-diiodobutane to improve mechanical strength and was added with MoPA to increase proton conductivity. MoPA should be fixed to back bone of SPEEK to prevent bleeding out. Therefore, the carbonyl group of SPEEK was reduced with NaBH4 and 3-isocyanatepropyltriethoxysilane (ICPTES) was added. The MoPA bonded composite was produced in the reaction of MoPA with 3-mercaptopropyltrimethoxvsilane (MPTMS). In conclusion, MoPA bonded CL-SPEEK composite membrane featured 0.129 S/cm of proton conductivity at $80^{\circ}C$, and 2,156 hours of chemical stability in Fenton test. These properties are better than those of membranes of other SPEEK system.